Sensitive and emotional, Lavender shows deep concern for Professor Trelawney, of whom she is quite fond, when Professor Umbridge dismisses her publicly—she and Parvati Patil brought the distraught teacher flowers (OP26). Lavender also cares for animals, such as her pet rabbit Binky, who dies in her third year while she is at Hogwarts (PA7).

Relationship with Parvati Patil

Relationship with Professor Trelawney

Relationship with Ron Weasley

Lavender as a first-year

Lavender is the first student to be Sorted into Gryffindor House in 1991.
Lavender becomes close friends with Parvati Patil, but neither of them becomes close to Hermione Granger. It is Parvati who tells Lavender that Hermione is crying in the girls' bathroom on their first Halloween at Hogwarts; Harry overhears the conversation, which leads him and Ron Weasley to find Hermione—and fight a troll in the process (PS10).

Lavender as a second-year

Lavender, like most Hogwarts students, finds it difficult to maintain interest in the drawn-out lectures during History of Magic classes, but when Hermione asks Professor Binns about the legend of the Chamber of Secrets, she immediately begins to pay attention (CS9).

Lavender as a third-year

As she becomes older, Lavender develops a habit of giggling and squealing with her best friend, which increases when they start to have Divination lessons. She becomes even more interested in the subject after Professor Trelawney predicts that something that she fears will happen on October 16, 1993—Lavender receives a letter from home on this day telling her that her pet rabbit Binky has died (PA6, PA7).

Lavender asks Harry to remember his tea leaves when the boy volunteers to approach a Hippogriff, after being deeply impressed by the divination professor's announcement that he had the ominous omen of the Grim in his cup (PA6). Even before her rabbit dies, she and Parvati start going to Trelawney's room during lunch times and coming back with "superior looks" on their faces (PA7).

When Hermione decides to drop Divination, Lavender points out that the professor predicted that someone would be leaving them forever around Easter (the time when Hermione drops) (PA15). Later she brags about her talent for divining, claiming to have seen many things in the crystal ball during her final exam in the class (PA17).

Lavender as a fourth-year

During Hagrid's first lesson in their fourth year, Lavender is one of the first students to reach for the Blast-Ended Skrewts. She squeals 'eurgh' on first seeing them, a sound which "just about summed up the Blast-Ended Skrewts, in Harry's opinion" (GF13). Later, she gets very excited when the class starts covering astrology in Divination classes; when Trelawney tells Lavender that her hidden planet is Uranus, Ron asks if he can see it, making a crude joke (GF13).

Lavender's giggling increases considerably when Professor McGonagall tells the students about the upcoming Yule Ball, especially when the teacher tells them it is an opportunity to let their hair down. She attends the party with Seamus Finnigan, but the relationship between the two does not develop further (GF22).

Lavender as a fifth-year

After Cedric Diggory's death in the third task of the Triwizard Tournament and Dumbledore's annoucement about Lord Voldemort's re-birth, Lavender returns to the school after a summer of reading the Daily Prophet. As Harry sits at the Gryffindor table during the start-of-term feast, she stops talking to her best friend to greet him friendly, trying hide the fact that she and Parvati were talking about him (OP11). After the feast, when the students return to their dormitories, Lavender tells Hermione that she doesn't believe Harry, but Hermione promptly shuts her up (OP12).

Lavender and Parvati often laugh at Luna Lovegood's eccentric choices of jewellery, especially after seeing the Ravenclaw wearing her raddish earrings on her way out of Herbology class, but after Ernie Macmillan claims that he believes Harry about Voldemort, Lavender stops smiling (OP13).

Both Parvati and Lavender are deeply disappointed when Hagrid returns to teach classes after visiting the giants and replaces Professor Grubbly-Plank (OP21). The girls are also quite unhappy about Umbridge's decision to put Professor Trelawney on probation; when the High Inquisitor decides to sack the Divination professor, the two hold each other and cry during the professors' argument. Despite their loyalty to Trelawney, the girls are nevertheless pleased when Firenze is instated as their new Divination teacher (OP26).

After Umbridge sends Aurors to capture Hagrid and McGonagall, trying to stop them, is hit by seven different stunningspells, Lavender tearfully expresses her wish for her Head of House to recover (OP30).

Lavender as a sixth-year

On beginning her sixth year, Lavender's actions towards Ron become flirtatious. She laughs at his least funny comments and smiles at him every time he passes. When Ron attends the tryouts for Gryffindor's Keeper, she screams "Good Luck" from the seats, and looks annoyed by Hermione's closeness to the redhead (HBP11). Before the first match of season, against Slytherin, she tries to raise the boy's morale, saying that he will be brilliant.
After winning the game, and having an argument with Hermione, Ron decides to make a move, and they spend most of the celebration party kissing each other in their common room. When they decide to go somewhere more private, they walk in on Harry and Hermione talking in a empty classroom, and Lavender exits, leaving the trio alone. Hermione, who had already invited Ron to Slughorn's Christmas party, is very annoyed with him, and sets the birds she had Conjured on him (HBP14).

Following this, Lavender and Ron start a very physical relationship, which often embarrasses both Harry and Parvati—Hermione refuses to stay in the common room while they are snogging. After Hermione announces that she will attend Slughorn's party with Cormac McLaggen, both Lavender and Parvati spend a while talking about the news (HBP15).

During the Christmas holidays, Lavender sends Ron a golden chain with the words "My sweetheart" written on it, which disgusts her boyfriend (HBP16). She starts calling the boy Won-Won and spends more time with him, almost to the point of being clingy. Her behavior starts to annoy Ron, and he avoids her as much as possible (HBP17). When Ron accidentally eats chocolate cauldrons infused with a love potion that Romilda Vane had sent to Harry, he mistreats his girlfriend, at which Lavender looks very annoyed (HBP18).

She becomes increasingly irritated (and, to some, irritating) as she feels Ron and his friends increasingly pushing her aside. For example, Harry does not tell Lavender when Ron drinks poisoned mead and is sent to the hospital wing, something about which she complains to the Boy Who Lived. She also starts to spend more time in Harry's company, constantly asking him about Ron and her relationship with him. When Harry asks her why she doesn't ask Ron instead of him, Lavender tells him that she did not manage to see Ron awake while in the infirmary (HBP19). She starts to show signs of jealousy regarding Ron and Hermione's friendship. When Ron leaves the hospital wing without telling her, and—to make matters worse—goes to his first breakfast out of the infirmary with Hermione, she snaps, sparking a big argument with her boyfriend (HBP20).

When Harry leaves the boys' room under the Invisibility Cloak with Ron and Hermione, Lavender starts making a scene in the common room (HBP22). She and Ron break up, and for a long time, Lavender cries every time she sees Ron and Hermione together (HBP24).

Lavender as a seventh-year

As Lavender Brown returns to Hogwarts to finish her seventh year there, we see very little of her in this book. She is one of the members of Dumbledore's Army who are found to be living in the Room of Requirement when Harry gets back to Hogwarts.

As Harry, Ron, and Hermione escape the castle on their way to the Shrieking Shack, they see Lavender, who has just fallen from a balcony in the Entry Hall, attacked by a grey blur that Harry at first takes for an animal. Hermione jinxes the blur, which Harry now recognizes as Fenrir Greyback. Fenrir is then knocked unconscious by a flying crystal ball, sent his way by Sibyll Trelawney.
It is unknown if Lavender and Hermoine did become friends after the war But it is most likely they'll grow to be somewhat friendly. After all, Lavender owns Hermione her life which think they'd hang out in groups of people, wave when they saw each other, make small talk,ect